net/mlx5e: Fix RQ SW state layout in RQ devlink health diagnostics

Remove nesting level before RQ's SW state title and before RQ's SW
state capabilities line.

Preceding the RQ's SW state with a nameless nesting, wraps the inner SW
state map/dictionary with a nameless dictionary which is prohibited in
JSON file format.

Removing preceding SW state nest by removing function call
devlink_fmsg_obj_nest_start() and devlink_fmsg_obj_nest_end().

Signed-off-by: Adham Faris <afaris@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>